Modern embedded computing applications rely heavily on the storage of and access to data. However, large memory devices are often at odds with the space and cost constraints of embedded applications. Recently, Microchip announced two new serial SRAM products, both of which boast larger densities and increased speeds.
Microchip’s 23AA02M/23LCV02M and the 23AA04M/23LCV04M. Image used courtesy of Microchip
Let’s take a look at Microchip’s new products and discuss why these devices can be an appealing alternative to traditional parallel SRAM offerings.
Microchip Unveils Two Serial SRAM Devices
Microchip claims its two new serial SRAM products, the 23AA02M/23LCV02M and the 23AA04M/23LCV04M, are major steps forward in its product portfolio.
The 23AA02M/23LCV02M has a storage capacity of 2 Mb, while the 23AA04M/23LCV04M doubles the capacity to 4 Mb. These SRAMs offer flexible physical packaging options: 8-lead PDIP, SOIC, and TSSOP for the 2 Mb versions and 14-lead packages for the 4 Mb versions.
The 23AA02M/23LCV02M serial input timing diagram. Image used courtesy of Microchip
These SRAMs support a single-voltage, read-and-write operation, with the 23AA02M and 23AA04M variants accommodating a range from 1.7 V to 3.6 V, and the 23LCV02M and 23LCV04M designed for a slightly narrower range of 2.2 V to 3.6 V. This flexibility caters to low-power applications and those requiring more power efficiency. In that same vein, these SRAMs address power consumption concerns with low active read current specifications (6 mA max at 40 MHz, 3.6 V for SPI/SDI/SQI) and a standby current of just 140 μA typical at 25°C.
One of the most notable features of these serial SRAMs is their serial interface architecture, which is compatible with SPI, SDI, and SQI protocols. The SRAMs are also designed for data reliability, with built-in error correction code (ECC) logic, ensuring data integrity and reducing the likelihood of errors. More information can be found on Microchip’s Memory Products page.
Serial SRAM and Speed
With these two new devices, Microchip sought to address a major pitfall of serial SRAM: its significantly lower bandwidth than a parallel interface. Serial SRAM offers non-volatile storage while facilitating high-speed data access and operation. Unlike traditional SRAM, which typically uses a parallel interface and requires numerous connections and pins for data, address, and control signals, serial SRAM employs a serial interface. This interface significantly reduces the pin count and simplifies the design and interconnection with microcontrollers, microprocessors, and other digital systems.
Serial SRAM operates using a simpler communication protocol, often the serial peripheral interface (SPI) or the inter-integrated circuit (I2C), which limits data transfer to one bit at a time over a serial connection. This serial data transfer mechanism enables a smaller and more cost-effective physical package, making it an effective choice for complex or space-constrained applications and those where the cost of additional pins and traces is prohibitive.
Serial versus parallel communication. Image used courtesy of Digi-Key
While a parallel interface can send many bits of data at the same time, serial interfaces must send data bits one at a time, slowing down communication between SRAM and the host. Speed is a particularly important specification for serial SRAM since it directly impacts system performance and efficiency. In real-time applications, such as digital signal processing or high-speed data acquisition, these devices must quickly write to and read from memory without significant delays. With these applications in mind, Microchip designed its new serial SRAM devices to support high-speed clock frequencies up to 143 MHz, significantly improving data throughput compared to previous generations.
Supporting Embedded Applications
In designing these new serial SRAMs, Microchip prioritized small form factor, low power, and high density, so the devices can be used in applications involving continuous data transfer and data-intensive workloads. The devices are now available in quantities up to 10,000 units.
